DSLR data and different ISO values of flats and lights  

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(@jeroenm)
White Dwarf Customer
Joined: 1 year  ago
Posts: 20
September 17, 2018 15:43  

Hi Mabula,

 

Since a few days I'm using my Nikon D7100 DSLR, together with my SW Esprit 80mm APO. The exposure time of the lights was 600 sec @ ISO 1600 so I also created some 50 darks with the same exposure time and ISO.

Since my flatpanel is quit bright, I decided to take the flat frames at ISO 200 to get a decent exposure time (3.3 secs). I also made 50 dark flats @ ISO 200 and around 250 BIAS frames @ ISO 200.  

I didn't make a BPM yet for this camera (using the flats and darks), but was wondering about 2 things:

• is it possible to create a BPM using darks and flats that are of different ISO-settings? Or should I use the dark flats?

• in the older versions of APP there was a button "details" in the top center which I always used to check the percentage 

of cold and hot pixels (should be around 3%), but this button is removed in the latest version of APP.

 

Kind regards,

Jeroen

 

 

This topic was modified 2 months  ago by Jeroen

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(@mabula-admin)
Quasar Admin
Joined: 2 years  ago
Posts: 1797
October 14, 2018 13:56  

Hi Jeroen @jeroenm,

Please accept my apologies for my late response.

In repsonse to your questions:

is it possible to create a BPM using darks and flats that are of different ISO-settings? Or should I use the dark flats?

A Bad Pixel Map is not ISO dependent for almost all camera's. I suggest you create a single BPM using a nice set of flats and darks. Regarding the darks, use at least 20. More is better. And the longer exposure the exposure time, the better as well. It will give better statistics on the non-linear pixels. So 50 darks with exposures of at least 2 minutes I would suggest 😉 . Darks made with higher temperature are actually better to create your Bad Pixel Map for the same reason as using longer exposure times.

in the older versions of APP there was a button "details" in the top center which I always used to check the percentage

of cold and hot pixels (should be around 3%), but this button is removed in the latest version of APP.

Please see the release notes about this, the left side of the image viewer can be moved to see the metadata 😉

https://www.astropixelprocessor.com/community/release-information/astro-pixel-processor-1-062-ready-for-download/

3rd release note:

  • Improved, Image Viewer Meta Data, the details checkbox, above the image viewer has been made redundant. You can now see the image metadata together with your image data. There is a splitpanel that you can move all the way from left to right now.

MetaData ImageViewer Panel both
MetaData ImageViewer Panel  metaData
MetaData ImageViewer Panel image

Main developer of Astro Pixel Processor and owner of Aries Productions


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